Well Pressure Switch Settings: 30/50 vs 40/60 Explained

The short answer

A pressure switch starts the well pump at the cut-in pressure and stops it at the cut-out. Most homes use 30/50 or 40/60 psi. Moving from 30/50 to 40/60 gives noticeably stronger showers, provided the pump can comfortably build 60 psi at your well depth and you reset the tank precharge to 38 psi. Adjust with the power off: turning the large nut clockwise raises both settings together; the small nut changes the gap between them.

What the numbers mean

Common pressure switch settings
Setting	Feels like	Tank precharge	Notes
20/40	Weak	18 psi	Older or low-head systems
30/50	Adequate	28 psi	Common factory default
40/60	Strong	38 psi	The usual upgrade; pump must reach 60 psi
50/70	Very strong	48 psi	Needs a pump and switch rated for it; more pipe stress

The 20 psi gap between cut-in and cut-out is standard; a wider gap means longer pump runs and fewer starts, but bigger pressure swings at the tap.

Can your pump reach the higher setting?

Pumpendium mathHead needed at cut-out = pumping water level + (cut-out psi × 2.31) + friction. Raising cut-out from 50 to 60 psi adds about 23 ft of head. If your pump's curve is already near its limit at 50 psi, it may never reach 60 and will run continuously.

After raising the setting, watch a full cycle. If the pump runs for a long time near the top and never shuts off, it cannot reach the cut-out; lower the setting or upgrade the pump. See deep well submersible pumps.

Adjusting the switch

SafetyPressure switches carry 120 or 240 V on exposed terminals. Switch off the breaker for the pump before removing the cover, and keep fingers away from the contacts.

Note the current cut-in and cut-out on the system gauge by running water and watching when the pump starts and stops.
Turn off the pump breaker and remove the switch cover.
To raise both settings together, turn the large nut on the tall spring clockwise; each full turn adds about 2 to 3 psi on common switches.
To change only the cut-out (widen the gap), turn the small nut on the short spring.
Drain the system, set the tank precharge to 2 psi below the new cut-in, then restore power and watch a full cycle.

A switch rated 30/50 can often be adjusted to 40/60, but buying a switch factory-set at 40/60 is simple and cheap. Replace switches with pitted or burned contacts. Related: pressure tank sizing and precharge.

Troubleshooting

Pump short-cycles: usually low precharge or a waterlogged tank, not the switch.
Pump will not stop: cut-out set higher than the pump can reach, or a leak.
Pump will not start: burned contacts, a clogged pressure tube under the switch, or a tripped low-pressure cutoff lever on switches that have one.
Chattering contacts: a clogged switch nipple or a failing switch.

Products mentioned

Pressure switch · Square D

Square D FSG2J21CP 30-50 psi Pressure Switch

30-50 psi, 1/4 in.

Square D

Pressure switch · Telemecanique

Telemecanique 9013FSG2J24 40-60 psi Pressure Switch

40-60 psi, OEM.

Telemecanique

Shallow well jet · Red Lion

Red Lion RJS-100-PREM Shallow Well Jet Pump

1 HP, 23 GPM.

Red Lion

Questions readers ask

Is 40/60 better than 30/50?

For shower strength, yes. It works as long as your pump can build 60 psi at your well depth and you reset the tank precharge to 38 psi.

How do I adjust my well pressure switch?

With the power off, turn the large spring nut clockwise to raise both cut-in and cut-out, or the small nut to change the gap. Then reset the tank precharge to 2 psi below the new cut-in.

What should my well tank pressure be with a 40/60 switch?

38 psi, measured with the pump off and the water drained from the tank.

Why does my well pump not shut off?

Often because the cut-out is set higher than the pump can reach. Lower the setting slightly or check the pump's capacity at your well depth.